My first was Suteki da ne by Rikki somewhere in 2002-2003 I think. I didn't know much about japanese during that time. Then I heard Hikki's Hikari, and when my anime fandom began in 2004, I got lost into japanese music for good <3 I listened to anime songs though most of the time. My j-pop fandom officially began in 2005-2006 with Hikki as I have said before somewhere lol.
And now I'm obsessing with K-pop. My first K-pop song was somewhere 2008-2009 I think, and the song was Tell me by Wonder Girls if I'm correct.

I didn't care about it that much during that time but when I began listening to BoA on Christmas 2009, I got interested in korean music as well.

So thanks to BoA that I found the amazeness of the K-pop